A variety of electrical energy storage devices make use of feedthrough pins that act as terminals for the device. One of the challenges presented by feedthrough pins is creating a seal between the case of the device and the feedthrough pin. The integrity of these seals must be able to withstand the pressures generated within these devices. In devices such as batteries, the integrity of these seals must be able to tolerate the corrosive nature of electrolytes within the case. Further, the seal must be simple enough to be practical for device fabrication. As a result, there is a need for a seal that is suitable for use in fabrication of electrical energy storage devices.